I was curious as to how many combinations of basic ‘down up’ strums are possible in a measure of 4/4, so I put together this PDF containing all 256 possible strums given:
Π = Downstrum
V = Upstrum
– = Space to let the strings ring
Each of these elements takes up an eighth note's space. Some of the strums are readily useful and others are not, but it is nice to have a reference to all the possibilities. You might use some of them for strum 'sight reading' in helping to learn strum notation and keeping a steady beat while strumming.